ZOOLOGY AN 1 1 BOTANY, MICROSCOPY, ETC. 749 



was discoYered by Fraser in H. rutilans at the third mitosis in the ascus, 

 and he finds his own results verified in three other species, Peziza 

 Catinus, Galactinia succosa, and Pustularia vesiculosa. 



Mildews of Cereals.* — A long series of experiments is tabulated by 

 G. M. Reed, and results explained in connection with his work on 

 cereals. All such experiments have in view the finding of plants 

 immune to disease. Reed proved that mildew on oats occurs on species 

 of Arena only ; barley mildew only on Hordeum ; rye mildew is confined 

 to species of Secale ; and wheat mildew to species of Tr it team. An 

 account is further given of infection experiments on hybrids of these 

 various grasses : and, finally, in reviewing the evidence of immunity, the 

 writer adds that external conditions play a prominent part in deter- 

 mining whether a plant is immune or susceptible to a given fungus- 

 disease. The influence exerted by these conditions requires investigation. 



Hypocreales of N. America : II. f — J. Seaver has united in Tribe II. 

 Creonectriese, all genera and species of this group that possess a 

 stroma. With some of these, e.g. Sphserostilbe, we are already acquainted ; 

 the new genera are Sphserodermatella, in which there is a csespitose 

 arrangement of perithecia ; Creonectria, which includes the species of 

 Nectria that are stromatoid : Macbridella, distinguished by the coloured 

 spores ; Scoleconectria, with elongate many-septate spores ; and Thyro- 

 nectroidea, with muriform coloured spores. All the species are fully 

 described ; none of them are new. 



Xylaria polymorpha4 — F. Gueguen reports several new observations 

 in his cultural study of this fungus. He made cultures on carrot, and 

 obtained stromata exactly comparable with the growths on the original 

 wood. They were not appreciably affected by the presence or absence of 

 light. No fructifications were obtained except from April to the end of 

 October. Variations in form were produced owing to differences in 

 atmospheric conditions, which explains also the variations seen in so 

 many of the larger fungi from season to season, and should lead to caution 

 in the determination of new species. 



New Genus of Mucedinese.§ — P. Hariot and N. Patouillard re- 

 ceived from M. Chevalier fruits of Zizyplms Baclei deformed by a fungus 

 which proved on examination to be a Mucedine, Coniodictyum Cheva- 

 lieri g. et sp. n. It is distinguished by its muriform colourless spores, 

 yellowish-white in the mass. In the centre of the fruits there is a fine 

 branching mycelium, from which rise short upright conidiophores, each 

 with a muriform conidia at the tip. 



Hyphomycetes.||— In this fascicle Lindau finishes the large genus 

 Fusarium. The two small sections Dictyosporge and Staurosporge are 



* Bull. Torrey Bot. Club, xxxvi. (1909) pp. 353-88. 



t Mycologia, i. (1909) pp. 177-207 (1 pi.). 



t Bull. Soc. Mycol. France, xxv. (1909) pp. 89-97 (1 pi.). 



§ Tom. cit., pp. 13-14 (12 figs.). 



|| Rabenhorst's Kryptogamen-Flora, 9te Abt. lief. 114 (Leipzig, 1909) pp. 561-624. 



